Vacuum relay



1 J. E. JENNINGS 2,912,541-

VACUUM RELAY Filed June 22, 1956 ANTENNA RECE/VEP /NVE N TOR J0 E MMETT JENNINGS v ia wfa b/ls AT TORNE Y United States Patent VACUUM RELAY Jo Emmett Jennings, San Jose, Calif., assi'gnor to Jennings Radio Manufacturing Corporation, San Jose, Calif., a corporation of California Application June 22, 1956, Serial No. 593,211

7 Claims. (Cl. 200-98) My invention relates to relays; and particularly to a single pole, double throw relay enclosed in a vacuumized envelope.

One of the main objects of my invention is the provision of a vacuum relay operable at high voltages and high currents at high speeds.

Another object is the provision of such a relay of small size, and with its moving parts enclosed within a vacuumized envelope.

Still another object is the provision of a high speed vacuumized relay having means for adjusting the spacing between the enclosed contacting parts.

Another object is the provision of a vacuumized electromagnetically operated relay having removable pole pieces and external coils which are readily removable and replaceable. j. 7

My invention possesses other objects, some of which will be brought out in the following description of the invention. I do not limit myself to the showing made by the said description and the drawings, since I may adopt variant forms of the invention within the scope of the appended claims.

Referring to the drawings:

Fig. l is a vertical half sectional view, partly in elevation. The relay control circuit is shown schematically.

Fig. 2 is a fragmentary elevation taken in the direction indicated by the arrow 2 in Fig. 1.

Broadly considered, the vacuum relay of my invention comprises an evacuated envelope including a dielectric portion having a metallic end cap hermetically sealing each opposite end thereof. A plurality. of contact rods extend into the envelope through the dielectric portion thereof, constituting spaced contact points within the envelope, and spaced terminal leads outside the envelope. Hermetically sealed to one of the end caps and extending into the envelope is an expansible metallic structure, on the inner end of which is pivotally mounted a conductive and magnetiz'able rocker adapted to oscillate between selected contact points within the envelope. Means external to the envelope are provided to adjust the position of the rocker to compensate for wear of the contact points, and to vary the frequency of its oscillations.

Mounted on the opposite end cap are a plurality of electromagnetic coils, each wound on a soft iron core, and positioned so that oscillation or rocking of the rocker may be controlled by alternately energizing a selected electromagnetic coil.

The vacuum relay of my invention finds utility as a keying relay to key telegraph transmitters, and also as a transmit-receive switch in radio frequency communication. The switch or relay may be used to transfer direct or alternating current alternately from one source to two different loads; and as an interrupter for direct current in the conversion of low voltage battery power to high voltage direct current.

In more specific terms, my vacuum relay comprises an evacuated envelope formed by a glass shell 2 symmetrical 2,912,541 Patented Nov. 10, 1959 about a longitudinal axis 3, and having hermetically sealed metallic end caps 4 and 6 at opposite ends thereof.

The end cap 4 serves conveniently as one of the terminals of the relay and is formed preferably from copper to provide a hollow open-ended cylindrical terminal section 7 and a conical flange 8 integral therewith and hermetically sealed to one end of the glass shell 2.

The openended cap 4 is hermetically sealed by a hollow metallic bellows 9 having a closed mobile end 12 extending into the envelope, and its outer open end 13 integrally fixed within the cylindrical terminal section 7. Thus, the metallic bellows forms a conductive expansible structure adapted to be expanded inwardly of the envelope by atmospheric pressure acting on the interior thereof. Expansion and contraction is controlled by a metallic stem 14, integral at its inner end 16' with the closed mobile end 12 of the bellows, and extending outwardly from the bellows to provide a threaded end portion 17.

A hearing tube 18, integrally brazed to the end cap 4 and bellows, and extending into the latter, provides a bearing 19 to slideably receive and guide the stem 14 when it is axially moved. Adjustment of the stem axially to effect contraction of the bellows or to allow expansion is effected by an adjustment nut 21 threaded on the portion 17 of the stem and bearing against the outer end of the bearing tube. A second nut 22 locks the first in adjusted position.

Integrally brazed horizontally on the inner end of the bellows is an apertured plate 23 having spaced integral flanges 24 vertically depending therefrom and forming fixed journals for opposite ends of a horizontal shaft 26. The shaft serves to pivotally journal a conductive magnetizable rocker comprising a horizontally extending steel plate or armature 27 having vertical side flanges 28, fitting within the depending plate flanges 24, and journaled on the shaft 26. Each flange 28 tapers from a high point at the mid-portion of the plate to each opposite end of the plate where it converges with the plate. The plate is integrally and flexibly connected to the bellows end 12 by a highly flexible pigtail or conductor 29 looped so as to have each of its two ends 31 brazed to the plate 27, and its midpoint 32 brazed to the inner end 12 of the bellows. A continuous conductive path is thus provided for the flow of current between the rocker and the bellows. In some instances it may be desirable to form the pigtail from a resilient metallic strip positioned so as to tilt the rocker in a direction to form a normally open ora normally closed circuit through the relay.

Brazed on the upper side of the plate 27 adjacent each end is a contact pad 33 formed from a short length of tungsten. Each pad provides an extremely long life contacting surface positioned to engage and disengage the contact end surface 34 of an associated contact point 36. Each contact point is radially spaced from and parallel to the axis line 3 of the relay, and the end surface 34 of each lies in a horizontal plane common to both. The contact points are preferably formed by the inner ends of tungsten rods which are bent radially outwardly in portions 37 passing through and hermetically sealed in the dielectric shell 2, and constituting external terminal leads outside the envelope.

As shown in Fig. l, the contact rocker 27 is pivoted midway between the two contact points; and the contact pads 33 are each spaced a short distance from the end 34 of the point. Expansion and contraction of the expansible structure controls the extent of this space, and the extent of the space is a factor in the current-carrying capabilities and speed of operation of the relay.

Oscillation or rocking of the rocker makes or breaks an electrical circuit between the terminal cap 4 and one or the other of the contact rods 37.

To .eifect oscillation of the rocker, an electromagnetic control circuit is provided. The end cap 6 of the relay is formed with a plurality of inwardly extending and outwardly opening cylindrical sockets or thimbles 38, the bottom wall 39 of each of which lies in a horizontal plane parallel to and spaced from a plane coincident with the end faces 34 of the contact points. One of said thimbles is associated with each contact point, and the space between bottom Wall 39 of each and end face 34 is such as to permit the loose accommodation therebetween of the associated end of the rocker. A centrally positioned thimble 41 having a bottom wall 42 is provided with a metallic stem 43, integrally brazed in the thimble and extending outwardly therefrom in a bracket stud 44 to which may be demountably secured a plurality of cylindrical magnetic cores 46.

Each magnetic core comprises a soft iron rod having one end inserted into a thimble, and its other end extending outwardly therefrom in an end portion 47 having a conductive coil 48 wound therearound. The coil end portions 47 of the cores are connected by a soft iron cross bar 49 brazed thereto and secured to the bracket stud 44 by screw 51. Thus, a demountable, U-shaped electromagnet assembly is formed having magnetizable pole pieces 46 extending into thimbles 38.

As shown schematically in Fig. l, the control circuit for the electromagnet assembly includes a source 56 of direct current having one terminal connected by suitable leads 57 to corresponding ends of the coils 48. The other terminal is connected through a manually operable switch or key 58 with one or the other of leads 59 and 61, connected to the other corresponding ends of the coils 48. Movement of the switch to connect with lead 59 thus energizes the left hand coil, causing the associated pole piece 46 to be magnetized and exert a downward pull on the left end of the rocker, tilting it so as to effect engagement of its right end with the right hand contact point 36. In this position of the parts the magnetic circuit follows the path of least resistance offered by cross bar 49 and bracket stud 44, thus intensifying the magnetic field within which the left end of the armature lies. 1 7

Movement of the switch or key to energize the lead 61 deenergizes the left hand coil and energizes the right hand coil, causing the rockerto tilt to the right. The speed of oscillation of the rocker depends on several factors including the moment of inertia of the rocker, permeability of the cores, current flowing through the energized coil, and rapidity with which the switch is keyed. When desired, a small current may be shunted around the switch or key 58 through a resistance 62, and applied to one of the coils so as to maintain a constant magnetic pull on one end of the armature. Such a connection will insure that the rocker will reciprocate to its normal position after each operation.

I claim:

1. A vacuum adjustable relay comprising a vacuurnized envelope having metallic end caps hermetically sealing opposite ends thereof, a plurality of contact rods extending into the envelope and constituting spaced contact points within the envelope and spaced terminal leads outside the envelope, a conductive expansible structure hermetically sealed to one of said end caps and extending into the envelope and including means outside the envelope for selectively adjusting the position thereof within the envelope, a conductive rocker pivotally mounted on said expansible structure within the envelope and selectively spaced from said contact points by adjustment of said expansible structure, and means on the other said end cap for effecting oscillation of the rocker to engage and disengage said contact points.

2. The combination according to claim 1, in which said conductive rocker comprises a metallic plate pivotally supported intermediate its ends on said conductive expansible structure.

3. The combination according to claim 1, in which said conductive rocker comprises a metallic plate pivotally supported intermediate its ends on said conductive expansible structure and each end of the plate is spaced equally from one of said contact points by selective adjustment of said expansible structure within the envelope.

4. The combination according to claim 1, in which means are provided forming an integral and flexible electrical connection between said expansible structure and said contact rocker.

5. The combination according to claim 1, in which said means for effecting pivotal oscillation of the rocker comprises a plurality of electromagnets associated with said rocker and operatively connected to oscillate the rocker to engage or disengage a selected contact point.

6. A relay comprising a vacuumized envelope having a dielectric shell and conductive end caps closing 0pposite ends of the shell, a pair of spaced thimbles mounted in one of the end caps with the closed ends within the envelope and the open ends outside the envelope, a core in each thimble, means for magnetising each core, a pair of conductive rods extending into the envelope, each rod terminating within the envelope in a contact point adjacent the closed end of a thimble, a conductive rocker arm pivotally mounted within the envelope and having each of its opposite ends interposed in spaced relation between a contact point and adjacent thimble, and conductive means adjustably connecting the rocker arm to the other end cap and selectively adjustable to vary the spacing of the rocker arm ends between said contact points and thimbles.

7. The combination according to claim 6, in which the cores are removable from the thimbles and are fixed to a cross bar, and a bracket to which the cross bar is detachably connected is arranged on the end cap between the thimbles.

References Cited in the file of this patent UNITED STATES PATENTS France Dec. 15, 1944 

